Polymer electrolyte fuel cells (PEFCs) are a type of fuel cell in which a polymer electrolyte membrane is used as an ion exchange portion. Due to their advantages such as operability at lower temperatures than the operation temperatures of other types of fuel cells and high power densities, PEFCs are highly expected to be widely used in the future. Cation exchange PEFCs using cation exchange membranes exchanging hydrogen ions have been commonly used. However, recently, anion exchange PEFCs using anion exchange membranes have been reported because, for example, they can generate electric power without using platinum catalysts which are expensive and susceptible to poisoning causing a decrease in the power output. Anion exchange PEFCs have great advantages such that liquid fuels (alkaline liquid fuels) such as alcohol and hydrazine can be used and that CO2 is not produced on the principle of power generation in the case where hydrazine is used as a fuel, although hydrazine is a liquid fuel. Non-Patent Literature 1 discloses an anion exchange PEFC in which hydrazine hydrate is used as a fuel.
Patent Literature 1 discloses, as a specific example of anion exchange membranes, an anion-conducting polymer electrolyte membrane obtained by selecting a hydrocarbon polymer film, radiation-graft-polymerizing the hydrocarbon polymer film with a monomer, and adding a quaternizing agent to impart ionic conductivity (in this membrane, the monomer is presented in the form of a monomer/diluent mixture, and the diluent contains alcohol and a hydrocarbon solvent). Patent Literature 1 also describes that the hydrocarbon polymer film is selected from the group consisting of low density polyethylene (LDPE) and high density polyethylene (HDPE).
In a PEFC, an anion exchange membrane is usually used in the form of a membrane electrode assembly (MEA) in which a catalyst layer is disposed on the surface of the membrane.